Crotonaldehyde, and

The reaction is readily illustrated by the formation of crystalline sorbic acid by the condensation of crotonaldehyde and malonic acid in hot pyridine solution ... 

With concentrated alkali, a resin is formed from repeated aldol condensations between aldol, crotonaldehyde and acetaldehyde. A similar condensation occurs with acetone (b.p. 56°), but the equilibrium mixture contains only a few per cent, of diacetone alcohol (III), b.p. 166° ... 

Preparing sorbic acid by reaction of crotonaldehyde and acetone followed by oxidation of the crotonyUdenacetone is of interest in the former Soviet Union (41,42) ... 

Manufacture of thiophene on the commercial scale involves reactions of the two component method type wherein a 4-carbon chain molecule reacts with a source of sulfur over a catalyst which also effects cyclization and aromatization. A range of suitable feedstocks has included butane, / -butanol, -butyraldehyde, crotonaldehyde, and furan the source of sulfur has included sulfur itself, hydrogen sulfide, and carbon disulfide (29—32). 

The earhest commercial route to -butyraldehyde was a multistep process starting with ethanol, which was consecutively dehydrogenated to acetaldehyde, condensed to crotonaldehyde, and reduced to butyraldehyde. In the late 1960s, production of -butyraldehyde (and isobutyraldehyde) in Europe and the United States switched over largely to the Oxo reaction of propylene. 

B eral, and xylene, phenol, ester, crotonaldehyde, and methylcyclopentane, in particular alcohol... 

The reaction of crotonaldehyde and methyl vinyl ketone with thiophenol in the presence of anhydrous hydrogen chloride effects conjugate addition of thiophenol as well as acetal formation. The resulting j3-phenylthio thioacetals are converted to 1-phenylthio-and 2-phenylthio-1,3-butadiene, respectively, upon reaction with 2 equivalents of copper(I) trifluoromethanesulfonate (Table I). The copper(I)-induced heterolysis of carbon-sulfur bonds has also been used to effect pinacol-type rearrangements of bis(phenyl-thio)methyl carbinols. Thus the addition of bis(phenyl-thio)methyllithium to ketones and aldehydes followed by copper(I)-induced rearrangement results in a one-carbon ring expansion or chain-insertion transformation which gives a-phenylthio ketones. Monothioketals of 1,4-diketones are cyclized to 2,5-disubstituted furans by the action of copper(I) trifluoromethanesulfonate. ... 

A recent patent describes the synthesis and catalytic use of Al-containing TUD-1 materials. Some of the reactions demonstrated inclnde hydrogenation of mesitylene (Pt as active metal) and dehydration of 1-phenyl-ethanol to styrene. Several other conceptnal reactions were also described, amongst others the Diels-Alder reaction of crotonaldehyde and dicyclopentadiene and the amination of phenol with ammonia. 

Sorbic acid has been prepared from crotonaldehyde 1 5 or aldol6 and malonic acid in pyridine solution by hydrogen peroxide oxidation of the condensation product of crotonaldehyde and pyruvic acid 7 and by the action of alkali on 3-hydroxy-4-hexenoic acid,8 9 /3,5-disulfo-w-caproic acid,10 and parasorbic acid.1112... 

Cyclic hydrazides 411 react with acrolein, crotonaldehyde, and methyl vinyl ketone either by heating in a sealed tube at 150 °C or by refluxing in aqueous ethanol containing a catalytic amount of sodium hydroxide, to provide acceptable yields of the corresponding products 412 (Equation 57). Both possible cyclic tautomers are detectable <2002EJO3447, 2002PCJ598>. 

It has been shown previously how water-soluble rhodium Rh-TPPTS catalysts allow for efficient aldehyde reduction, although chemoselectivity favors the olefmic bond in the case of unsaturated aldehydes [17]. The analogous ruthenium complex shows selectivity towards the unsaturated alcohol in the case of crotonaldehyde and cinnamaldehyde [31]. 

Table 15.7 Hydrogenation of crotonaldehyde and cinnamalde-hyde under 45 bar H2 at 140°C for 9 h.

Helmchen and colleagues used equimolar amounts of L-valine derived oxazaboroli-dine 361a to catalyze the reaction of methacrolein with cyclopentadiene (equation 103). Cycloadduct 322 was obtained with 64% ee229. The enantioselectivity was increased to 86% ee by using 60 mol% of 361a and donor solvents like THF. The same catalyst afforded the endo cycloadduct of crotonaldehyde and cyclopentadiene with 76% ee. 

As expected, the reactivity of crotonaldehyde and methyl vinyl ketone (MVK) is dominated by the reaction with the carbonyl moiety, leading... 

In catalysis, adsorbed CO may retard some reactions such as olefin hydrogenation, fuel cell conversion, and enantioselective hydrogenation. For instance, Lercher and coworkers observed the deactivation of Pt/Si02 in the liquid-phase hydrogenation of crotonaldehyde, and ascribed this deactivation to the decomposition of crotonaldehyde on platinum surface to adsorbed CO [138]. Blaser and coworkers found that the addition of a small amount of formic acid decreases the rate of liquid-phase hydrogenation of ethyl pyruvate on cinchonidine-modified Pt/Al203 catalyst, which they explained as the decomposition of formic acid on the catalyst to adsorbed CO. Interestingly, the addition of acetic acid does not decrease the reaction rate, but whether acetic acid decomposes on the catalyst as formic acid does was not mentioned [139]. 

Better reagents than lithium aluminum hydride alone are its alkoxy derivatives, especially di- and triethoxyaluminohydrides prepared in situ from lithium aluminum hydride and ethanol in ethereal solutions. The best of all, lithium triethoxyaluminohydride, gave higher yields than its trimethoxy and tris(/er/-butoxy) analogs. When an equimolar quantity of this reagent was added to an ethereal solution of a tertiary amide derived from dimethylamine, diethylamine, W-methylaniline, piperidine, pyrrolidine, aziridine or pyrrole, and the mixture was allowed to react at 0° for 1-1.5 hours aldehydes were isolated in 46-92% yields [95,1107], The reaction proved unsuccessful for the preparation of crotonaldehyde and cinnamaldehyde from the corresponding dimethyl amides [95]. 

Fig. 3b shows that the selectivity for dehydrogenation (based on detected products) was very low at low values of 0, but increased rapidly as the catalyst was reduced. On this catalyst, small amounts of crotonaldehyde and maleic anhydride were also detected. These amounts decreased slowly with increasing 0. 

Laboratory studies of the rearrangement process began with semi-continuous operation in a single, 200-mL, glass reactor, feeding 1 as a liquid and simultaneous distillation of 2,5-DHF, crotonaldehyde and unreacted 1. Catalyst recovery was performed as needed in a separatory funnel with n-octane as the extraction solvent. Further laboratory development was performed with one or more 1000-mL continuous reactors in series and catalyst recovery used a laboratory-scale, reciprocating-plate, counter-current, continuous extractor (Karr extractor). Final scale-up was to a semiworks plant (capacity ca. 4500 kg/day) using three, stainless steel, continuous stirred tank reactors (CSTR). 

Hydrotreating and Hydrogenation. - Nitride and oxynitride catalysts have been extensively investigated as catalysts for hydrotreating (in particular hydronitrogenation and hydrodesulfurisation) and hydrogenation (for CO, aromatics, crotonaldehyde and alkenes ° the reduction of NO with H2 has been covered in the previous section). 

The simple 1,2-dithiolenes, viz, 1,2-dithiolene (3, R H), 3-methyl-l,2-dithiolene (3, R Me) and the saturated derivative of the latter were detected by Takken and co-workers (2) with crotonaldehyde and butanedione as the starting materials. Ledl (33) identified 2-ethyl-4-methyl-l,3-dithiolene (4) in the reaction mixture containing propionaldehyde, hydrogen sulfide and ammonia, and the isomeric 2,4,5-trimethyl-l,3-dithiolane (5) was obtained by Sultan (29) from the reaction of acetaldehyde, aceto-in, and ammonium sulfide. 

Girard-T derivatives of chloroacetaldehyde, crotonaldehyde, and acrolein were not stable. Alternative methods were developed based upon the derivative formed by reaction of crotonaldehyde with hydroxylamine, and the formation of the hydrate of chloroacetaldehyde. 

Methyl ethyl ketone, crotonaldehyde, and acrolein react similarly with ethynylmagnesium bromide. The respective yields of acetylenic alcohols are 69%, 84%, and 40%. 

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